Yerkes Observatory - On November 30, 1901, astronomer and telescope maker, George Willis Ritchey, observes the heavens through the double slide-plate holder attached to the Yerkes 40-inch Refractor Telescope. ✨🔭 #YerkesObservatory #Astronomy #
New stewards for Yerkes Observatory offer an expanded mission and vision
40 inch refracting telescope at Yerkes Observatory in Williams Bay, Wisconsin Stock Photo - Alamy
Yerkes Obsevatory, still the world's largest refractor? - Observatories - Cloudy Nights
Wisconsin's Yerkes Observatory—stargazing through the world's largest refracting telescope